Higdon's left-footed strike, his 18th goal of the campaign, put Motherwell three ahead before the hour mark and made it 12 goals and three wins in total for the Steelmen against their Highland visitors.
Higdon opened the scoring on the half-hour mark with a more simple finish and Nicky Law netted Motherwell's second following a typical burst into the box.
Motherwell's 5-1 victory at Inverness in November proved Caley Thistle's only defeat in 21 games and their first since a 4-1 defeat on their previous visit to Fir Park.
Despite arriving on a five-match run without victory, which included four defeats, Caley Thistle's overall play had not dipped. But they were ultimately well beaten again by a convincing Motherwell display.
Kallum Higginbotham made an impressive first start for Motherwell following his loan move from Huddersfield and Stuart Carswell's hard work in midfield plugged the gap left by Keith Lasley's suspension, allowing Law to push forward to good effect.
Higginbotham looked to make an instant impact from his left midfield role with a long-range strike that flew not far wide, and then got in behind the home defence with a diagonal run, but no-one could reach his cutback.
Higdon then looped a header over following Stevie Hammell's free-kick.
Inverness, unchanged from the team that dominated against Kilmarnock but lost a last-minute equaliser, soon made an attacking impression with some short, sharp passing that created a number of half chances.
Billy McKay headed wide, Andrew Shinnie shot straight at Darren Randolph from 20 yards and Owain Tudur Jones curled wide from further out.
Shinnie had the ball in the net in the 26th minute when he followed in Aaron Doran's long-range strike that Randolph stopped, but he was ruled offside.
Motherwell regained control and Law worked a shooting chance following a one-two with Higginbotham, but his effort hit Higdon and spun wide.
Henrik Ojamaa was proving a threat peeling off to the left and Gary Warren was booked for bringing him down moments before he set up the opener.
The forward turned Warren and sprinted clear before attempting to shoot from the inside-left channel. He completely mis-hit his shot but it fell perfectly for Higdon to tap home from two yards.
More sharp passing from Inverness soon put Motherwell on the back foot and Doran swept the ball just over from David Raven's cutback.
But Motherwell finished the half on top and Higginbotham had the chance to double the lead when Carswell sent him clear on the break but he hurried his attempt to lob Ryan Esson and the keeper saved easily.
Ojamaa then had a shot blocked by Esson after a one-two with Higdon and Law sidefooted a volley wide after Chris Humphrey had returned the ball into the box.
Nick Ross fired over after running beyond the Motherwell defence in the opening moments of the second half but the hosts went two ahead six minutes in.
They side worked the ball to Ojamaa on the edge of the box following a throw-in and the Estonian's blocked shot spun up.
Law burst on to it and flicked the ball over Esson's head before converting at the second attempt despite the close attention of two Inverness defenders.
Ross Draper claimed for a handball in the box after his strike hit Carswell at close range but referee Calum Murray was not interested.
And Carswell helped set up Higdon's second in the 56th minute. The midfielder won Hammell's cross and his header looped up and fell invitingly for Higdon 16 yards out. The chance was difficult but the execution was perfect as Higdon kept his eye on the ball and arrowed a first-time volley into the far corner.
Inverness brought on Philip Roberts and Shane Sutherland up front but Motherwell continued to look more threatening with Humphrey twice coming close following strong runs.
Higginbotham and Ojamaa went off to standing ovations but there was little respite for the visitors and Law hit the underside of the bar with a powerful long-range strike.